docs(readme): Update README and add CLAUDE guidance

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CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Development Commands
+
+This project uses a Makefile with commands from `jbzoo/toolbox-dev`. The primary commands are:
+
+- `make update` - Install/Update all 3rd party dependencies via Composer
+- `make test` - Run PHPUnit tests
+- `make codestyle` - Run code quality checks (PHP CS Fixer, PHPStan, Psalm, etc.)
+- `make test-all` - Run both tests and code style checks
+- `make report-all` - Generate comprehensive reports (coverage, metrics, etc.)
+
+The project requires PHP 8.2+ and uses `jbzoo/toolbox-dev` for development tooling.
+
+## Architecture Overview
+
+This is a PHP retry/backoff library with the following key components:
+
+### Core Classes
+- `JBZoo\Retry\Retry` - Main retry orchestrator class
+- `JBZoo\Retry\Exception` - Base exception for the library
+
+### Strategy Pattern Implementation
+All retry strategies inherit from `AbstractStrategy` in the `JBZoo\Retry\Strategies` namespace:
+- `ConstantStrategy` - Fixed delay between retries
+- `LinearStrategy` - Linearly increasing delay (attempt * baseTime)
+- `PolynomialStrategy` - Polynomial delay (attempt^degree * baseTime), default degree=2 (quadratic)
+- `ExponentialStrategy` - Exponential delay (2^attempt * baseTime)
+
+### Key Features
+- **Jitter Support**: Configurable randomness to prevent retry collisions
+- **Wait Cap**: Maximum wait time limit for retry strategies
+- **Custom Retry Logic**: Pluggable decider callbacks for advanced retry conditions
+- **Error Handling**: Custom error handler callbacks for logging/monitoring
+- **Backward Compatibility**: Aliases for the original `stechstudio/backoff` library
+
+### Configuration
+The `Retry` class supports both constructor injection and fluent setters:
+- Constructor: `new Retry($maxAttempts, $strategy, $waitCap, $useJitter)`
+- Fluent API: `(new Retry())->setStrategy('exponential')->enableJitter()->run($callback)`
+
+### Function Interface
+Global `retry()` function provides a simple interface:
+```php
+use function JBZoo\Retry\retry;
+retry($callback, $maxAttempts, $strategy, $waitCap, $useJitter);
+```
+
+### Testing Structure
+- PHPUnit tests in `tests/` directory
+- Strategy-specific tests in `tests/Strategies/`
+- Package integration tests and alias compatibility tests
+- CI runs tests on PHP 8.2, 8.3, 8.4 with both `--prefer-lowest` and latest dependencies
+
+### Development Notes
+- Project enforces strict typing (`declare(strict_types=1)`)
+- Uses PSR-4 autoloading with namespace `JBZoo\Retry`
+- Includes global function definitions in `src/defines.php` and backward compatibility aliases in `src/aliases.php`
+- All classes are marked `final` for better encapsulation
+- Constants define default values and strategy names